Page 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Page 9Page 10Page 11Page 12Page 13Page 14Page 15Page 16Page 17Page 18Page 19Page 20Page 21Page 22Page 23Page 24Page 25Page 26Page 27Page 28Page 29Page 30Page 31Page 32J U L Y / A U G U S T 2 0 1 6 18 POTATO GROWER preplant, 3) 1 lb B/A applied 4 times as a foliar at the rate of 0.25 lb B/A starting at in mid-July and going until vine kill, 4) 1 lb B/A applied 2 times as a foliar at the rate of 0.5 lb B/A starting at in mid- July and going until vine kill, 5) 2 lbs B/A applied 4 times as a foliar at the rate of 0.25 lb B/A starting at in mid-July and going until vine kill, 6) 2 lbs B/A applied 2 times as a foliar at the rate of 1.0 B/A starting at in mid-July and going until vine kill. At harvest, total tuber yield, final tuber set, graded yield, tuber specific gravity, and internal dis- orders will be recorded at final harvest, usually mid to late September. A sub- sample from each plot tubers will be collected and evaluated for the presence or absence of stems as well as sugar analysis. Validation of a Nitrogen and Irrigation Model for Potato Production in Minnesota Rationale: Nitrate leaching during pota- to production continues to be a concern to the public and the industry. This is a major challenge because potatoes require high amounts of available nitro- gen to optimize yield, but because nitrate is so mobile keeping it in the root zone is difficult. Unpredictable rainfall can leach nitrate during the growing season; however, the amount leached is hard to measure. One approach to help manage nitrogen dur- ing the season is to use various models that take into account crop growth, water inputs and outputs and nitrogen inputs and outputs. A number of these models exist such as APEX, DSSAT, and EPIC, but they have not been tested or validated for potatoes grown under Minnesota conditions. This research is part of a larger MDA project in collabo- ration with Dr. David Mulla to develop a useable irrigation and nitrogen model for crop production in Minnesota. The overall objective is to obtain potato yield, nitrogen budgets, and water budgets under Minnesota conditions to validate selected models. These models can potentially be used to help guide N fertilizer and irrigation decisions during the growing season. The study will be conducted at the Sand Plain Research Farm in Becker, MN. Two irrigation treatments will be tested. One using the checkbook method and the other using plant and soil sensors to measure plant stress and soil water potential. Six N treatments will be imposed within each irrigation treatment: 1) starter N only, 2) 160 lb N/A as soluble N, 3) 160 lb N as ESN, 4) 240 lb N/A as soluble N, 5) 240 lb N/A as ESN, 6) N based on sensor measurements. Data generated from this study on N uptake, N leaching and water movement will be used to help validate selected models listed above. Nitrogen Response, Disease Incid- ence, and Soil Microbial Activity in Potato Cropping Systems as Affected by Fumigation This is a collaborative project being con- ducted by NDSU and U of M at the Sand Plain Research Farm in Becker. Fumigation is routinely used by potato growers to control soil-borne diseases. While the use of fumigation temporari- ly reduces disease incidence, it also eliminates the populations of beneficial soil organisms. Therefore, once fumiga- tion is used, repeated applications are necessary every time potatoes are grown in the rotation. Fumigation can have both positive and negative effects on nutrient use efficiency. Potato root sys- tems are often healthier following fumi- gation due to a lower disease incidence, which may in turn lower nutrient inputs. In contrast, fumigation substan- tially alters microbial diversity and could have negative impacts on nutri- ent cycling over time. This research is part of a comprehensive project to eval- uate the effects of fumigation sources on yield potential, nitrogen response, soil-borne disease incidence, and soil microbial activity and diversity. Specific objectives include: Determine the interactive effects of fumigation and nitrogen fertility on potato yield and quality, characterize the effect of fumi- gation on soil microbial activity, disease incidence, and nitrogen transforma- tions, and evaluate the effects of micro- bial inoculants on tuber yield and qual- ity in fumigated and non-fumigated soil. Potatoes have been grown in a 3- year rotation at this site since 2000 with the last crop of potatoes grown in 2014. Fumigation treatments include an untreated control, the recommended rate of Chloropicrin, and the recom- mended rate of Vapam. Application of fumigants occurred in October 2015. Within each fumigation treatment five nitrogen treatments will be evaluated: 1) a starter N control (30 lb N/A), 2) 120 lb N/A 3) 180 lb N/A, 4) 240 lb N/A, and 5) 300 lb N/A. A Field Evaluation of Aspire as a Potassium and Boron Source for Irrigated Potato Production Potatoes have a high demand for potas- sium (K), relative to other crops. K can influence the yield and size distribution of potato tubers, as well as their specific gravity and storage characteristics. Boron (B) is important in the integrity of the plant cell wall, where it binds pectins together, and in calcium absorp- tion. In both these roles, B availability is vital to tuber internal quality and storability, as well as yield. B can also increase the concentration of vitamin C in potato tubers. The importance of these nutrients to potatoes as an agricul-